Isle Royale National Park

Lake Superior, reached from Copper Harbor, Houghton or Grand Portage MN

One of the least-visited national parks in the lower 48. You get there by ferry or seaplane and walk everywhere once you arrive.

Best time: Mid-May to mid-September (the park is closed in winter)
Official info: National Park Service

Hikes and sights

About 40 mi, 4–5 days

The backbone of the island, running between Windigo in the west and Rock Harbor in the east.

Varies

Short loops to lookouts and old mining sites are possible if you do not want to backpack.

Ferry crossings take several hours and book early; confirm schedules on the NPS site.
Plan food, water treatment and fuel in advance. There are no roads or stores in the backcountry.
Campsite permits are required.

Distances are approximate and sources vary. Check the official page above for current trail conditions, fees and closures.